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4th Grade – Aurilio – Refraction with Jelly Crystals

Posted in 4th Grade, and Uncategorized

Mrs. Aurilio’s class has been learning about light during quarter two.  For our last lesson of the semester students were given a one inch sphere made out of polyacrylamide crystals.  “Jelly crystals.” This material absorbs many times its weight in water.  When properly formed it has the optical property of a spherical lens, yet feels like very firm Jello.

Students quickly experienced how easily the jelly crystals fractured.  In fact, small bits of this material, sold in gardening stores, can be mixed with potting soil and used with potted plants.  Once they soak up sufficient water, they prevent plants from drying out so quickly between waterings!

Students made a simple wire holder for their jelly sphere, creating an ~ 5 power magnifying lens.  Like a glass lens, light is refracted by the top and bottom surface of the jelly lens.  This type of refraction is the basis of all magnification tools.  Additional polyacrylamide crystals are available online at…

http://www.teachersource.com/product/growing-spheres/chemistry

 

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